The present invention relates to a method of forming a thin diamond film.
Conventionally, a thin diamond film has been formed (synthesized) on a substrate by means of the chemical gaseous phase growth method such as plasma CVD and photo CVD methods using hydrocarbon or organic compound gases.
Under the aforesaid conventional methods, however, the following problems have been present:
(1) Use of the hydrocarbon or organic compound gas causes graphite to separate as diamond crystals grow.
(2) The quality of the material usable for a substrate is limited to a great extent because the substrate and the gaseous atmosphere must be heated to high temperatures (e.g., about 800.degree. C. -1000.degree. C.).
(3) The kinetic energy of the ions produced in the gas phase roughly ranges from several 10 to several 100 eV to the atmost so that the energy of the ions arriving at the substrate is extremely small. Thus a diamond film is not fixedly adhered to the substrate and is apt to peel off.